(1) Field of the Invention
The present invention pertains to an apparatus that is one part of a conveyor system that transfers objects, for example plastic blow molded bottles, where the apparatus arranges the objects in layers on a pallet. In particular, the present invention pertains to an apparatus that is employed to quickly position two dimensional array layers of objects inside sealed, flexible bags while forming the sealed bags encapsulating each layer of objects prior to the layers of objects being delivered by the conveyor system to a palletizer.
(2) Description of the Related Art
Many product containers such as bottles, cans, jars, etc. are packaged in pallet load lots to facilitate their transportation from a manufacturer of the objects to a user of the objects. The pallet loads typically include large stacks of layers of the objects that are stacked on top of a supporting pallet. The layers of objects are secured to the top surface of the pallet by banding, plastic sheet wrap, or by other equivalent methods. The pallet and the layers of objects stacked on it can be moved as a unit from the manufacturer of the objects, through distribution and ultimately to the end user of the objects. Examples of conveyor systems that palletize layers of objects are disclosed in the Ouellette U.S. Pat. Nos. 6,106,220 and 6,371,720 B1, each of which are assigned to the assignee of the present invention and are incorporated herein by reference. In many conveyor systems in which objects are arranged in layers and are loaded onto pallets in stacks of the layers, the faster the conveyor system can operate to load pallets increases the overall cost efficiency of the system.
In palletizing conveyor systems such as those discussed above it is at times desirable to enclose each layer of objects to be palletized in packaging material to prevent the objects from being contaminated by dirt, dust or other foreign materials as the objects are transported from the manufacturer to the end user. This is particularly true in the manufacture of plastic blow molded bottles that are to be used as containers for various different types of food products. Conveyor systems have been designed that include a bagger apparatus that positions each layer of objects conveyed by the conveyor system in a bag and seals the bag closed prior to the layer of objects being stacked on a pallet by a palletizer. A typical prior art bagger apparatus includes a packaging material dispenser that dispenses packaging material in a tubular form to the conveyor system. A free end of the tubular packaging material is held open while a layer of objects is positioned inside the tubular packaging material by the conveyor system. Once the layer of objects is positioned inside a portion of the tubular packaging material, the open end of the tubular packaging material is closed and the tubular packaging material at the opposite end of the layer of objects is closed on itself to enclose the layer of objects inside the packaging material. The layer of objects enclosed inside the tubular packaging material is then separated from the remainder of the tubular packaging material which then encloses the next sequential layer of conveyed objects. The enclosed layer is then conveyed by the conveyor system to the palletizer that positions the layer of objects enclosed in the tubular packing material on a pallet.
The prior art method also included sequentially enclosing layers of objects in individual preformed bags through openings at the ends of the bags and then sealing the bags closed before palletizing the bagged layers. This method was at least as slow as the previously described method.
Bagging each layer of objects to be stacked on a pallet adds considerably to the time required to stack a pallet full with the layer of objects which detracts from the efficiency of the conveyor system The positioning of the tubular packaging material relative to the conveyor system where a layer of objects can be positioned by the conveyor system inside a portion of the tubular packaging material, and the subsequent closing of the tubular packaging material at opposite ends of the layer of objects prior to the enclosed layer of objects being palletized significantly adds to the time needed by the conveyor system to stack layers of objects on a pallet. What is needed to improve the cost efficiency of operating a conveyor system that arranges layers of objects inside a bag of packaging material prior to the layer of objects being stacked on a pallet is a more time efficient apparatus that positions layers of objects in enclosed bags of packaging material prior to their being stacked by a palletizer.